Reports of grape colaspis damage continue to come in from the western portion of Illinois. Mike Roegge indicated grape colaspis larvae have damaged roots in a number of producers' fields in the Quincy area. In fields showing aboveground symptoms, Mike dug plants and found several larvae near the root system of these plants. I have included one of the photos taken by Mike of the damaged roots.|
Damage from grape colaspis root feeding.
The cool, wet weather has slowed evaluation of many of the research trials currently being conducted by the University of Illinois. John Shaw, research scientist, Illinois Natural History Survey, is conducting a number of insecticide evaluation trials, and we will provide a summary of data as they become available. Early reports from Don Rhodes, Burrus Seeds, indicate good results from some insecticides in their evaluation trials. Randy Wright, research assistant, University of Illinois, has been sifting through pre-plant soil samples he collected in late April and early May looking for larvae. Recently, he has been back in these fields, assessing aboveground and belowground symptoms. Early next week, Randy will deploy different colored sticky traps to evaluate their attractiveness to grape colaspis adults.--Sue Ratcliffe